Biogeographic patterns of Early Cenozoic calcareous nannoplankton assemblages are delineated for the North and South Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. Nannoplankton assemblages are defined by Q mode Varimax Factor and Oblique Factor Analyses of census data on 44 taxa from 113 deepsea and landbased samples. Nanno classification, JNR 1 PROPOSALS FOR A REVISED CLASSIFICATION SYSTEM FOR CALCAREOUS NANNOPLANKTON We have recently been working on a new version of A Stratigraphical Index of Calcareous Nannofossils (Bown, in press).
During this work we needed to address the question of the classification of Cenozoic calcareous nannoplankton classification Young, JR; BOWN, PR; (1997) Cenozoic calcareous nannoplankton classification. calcareous nannoplankton floras. Many species characteristic of the late Eocene became ex tinct in the latest Eocene or early Oligocene.
Large calcareous nannofossils, particularly discoasters, are rare in the Oligocene, They are not, however, phylogenetically separate groups since there are significant common features between them (e. g. V and R mode calcification in heterococcoliths, Young et al. 1991), and since it is commonly accepted that the Cenozoic orders each originated, separately, from Mesozoic precursors (e. g. PerchNielsen 1979, Medlin et Calcareous nannoplankton mass extinction at the CretaceousTertiary boundary: An update, in Ryder, G.et al.eds.The CretaceousTertiary event and other catastrophes in Earth history.
Geological Society of America Special Paper, 307:. Jul 15, 2013 Calcareous nannoplankton represent a major component of oceanic phytoplankton, ranging in size from 0. 25 to 30 m. The first records are from the Late Triassic.
Their calcareous skeletons can be found in finegrained pelagic sediments in high concentrations and the biomineralization of coccoliths is a globally significant calcareous nannoplankton, while the presence, around the poles, of ice caps, accompanied by the instauration of cooler climatic modes, determined significant shifts in the species richness.
The biostratigraphy based on calcareous nannoplanktonis one of high resolution throughout the last 225 million,